Module "x" has no attribute "y", creating my own module .py

I am trying to create my own module (mi_modulo.py) and move there all the functions that I have defined in my Jupyter Notebook script, so that it looks cleaner.

However, when I am trying to use these functions that I have already moved to the module, I am not able to use them all, and I get the following message: module 'mi_modulo' has no attribute 'train4_data_import'

I have installed Anaconda 3.0 and I am running Python 3.7.0 through Jupyter Notebooks. (Forgive me if the expressions sound awkward, I know a bit of Python, but I am not really into all the installation, software, IDE, etc details.)

## mi_modulo.py ##

def train4_data_import(file_name):

    df = pandas.read_excel(file_name)

    force = df["Signal 1"].values[13:]
    acceleration1 = df["Signal 2"].values[13:]
    acceleration2 = df["Signal 3"].values[13:]

    return force, acceleration1, acceleration2

def hola_mundo():
    print("whatever")

## script ##

import pandas
import mi_modulo as mi

mi.hola_mundo()

mi.train4_data_import("Tren4.xlsx")

And this is what I get: (I was going to show an image but I am not sure how to do that with this stackoverflow new form style)

whatever

AttributeError                            Traceback (most recent call last)
<ipython-input-18-69a38929f7e6> in <module>()
      3 mi.hola_mundo()
      4 
----> 5 mi.train4_data_import()

AttributeError: module 'mi_modulo' has no attribute 'train4_data_import'

I don't understand why it is able to read one function but not the other.

----------------------------- EDIT 1 ----------------------------

Doing what U9-Forward suggests:

import pandas
from mi_modulo import *

hola_mundo()

train4_data_import("Tren4.xlsx")

I get now the following error:

whatever


NameError                                 Traceback (most recent call last)
<ipython-input-25-e1885200beb7> in <module>()
      3 hola_mundo()
      4 
----> 5 train4_data_import("Tren4.xlsx")

NameError: name 'train4_data_import' is not defined